http://en.wikipedia.org/wiki/Amblyopia
 3 main causes
1. Strabismic: by strabismus (misaligned eyes)
2. Refractive: by anisometropia (high degrees of nearsightedness, farsightedness, or
astigmatism in one or both eyes)
3. Deprivational: by deprivation of vision early in life by vision-obstructing disorders
such as congenital cataract
 Strabismus
o Lazy eye (eyes are misaligned)
o Usually normal vision in better eye, abnormal in the deviating/strabismic eye
http://www.ncbi.nlm.nih.gov.ezproxy.middlebury.edu/pmc/articles/PMC3275294/pdf/20110709.pdf
ClinicalEvidence. Amblyopia
Stephanie West, Cathy Williams
 Amblyopic kids: 38% were strabismic, 37% were anisometropic, and 24% were both
strabismic and anisometropic
 2-4% in kids up to 15 years old
 Definition: reduced visual acuity
 Causes
o High refractive error, conflicting visual inputs (because of squint)
 Untreatable after 7 to 8 years of age, some evidence suggests 7 to 12 years can be treated,
but recovery of normal vision is progressively less likely in older children
 Ideally treat between 3 and 5 years of age
 Adhesive patch: skin irritation, more expensive, kid can remove it excessively
 Felt patch on top of 1 lens of glasses: cheaper, no skin irritation but can look around patch
 Patching > spectacles (1.1 lines vs 0.5 lines improvement)
 Similar improvement with part-time and full-time patching…might as well just do 2h/day
Screening cost effectiveness
 Efficacy:
o 66% - age 3 and 4
o 63% - 5
o 47% - 6
o 0% - 18
 Treatment costs around $2000 ($1900 to $2100 from German cost estimate)
o $6.72 per preschool A/S screening, $17.00 per preschool photoscreening, and
$3.12 per kindergarten A/S screening
 Each child = $16 in amblyopia-related treatment costs
Amblyopia treatment outcomes
 Amblyopia leads to more vision problems later in life (ie blindness)
 Occlusion  74% better

Patients: amblyopia caused by anisometropia (unequal refractive power in both eyes),
strabismus (squint), or combo with full-time occlusion (FTO) wit
Amblyopia Treatment Outcomes
 Amblyopia treatment has never been standardized
 Occlusion (patching) – full-time/all waking hours
o Start full-time patching, wean off it, go back to part-time patching if vision
worsens after initial treatment
o Problem: social pressure, can cause complication of occlusion amblyopia
o Advantage: fewer compliance problems because children are used to always
wearing the patch
 Older = need longer treatment
 If occlusion of one eye does not equalize visual acuity or return preference to the
previously preferred eye, reverse occlusion is instituted
 Part-time patching also works, but full-time patching is effective in obtaining 20/30 or
better vision and produces equal vision at a higher rate than other treatments
Amblyopia Treatment
 1) Provide a clear retinal image
o Cycloplegic refraction (paralyze eye muscles to detect refractive error)
 2) Correct ocular dominance
o A) Occlusion therapy
 Patch the good eye to force fixation to the amblyopic eye.
 Prefer part-time occlusion for patients with binocular fusion &
amblyopia to maintain binocular fusion
 Full-time occlusion if constant esotropia (eyes turn inward) & no fusion
 Should have check-ups at intervals of 1 week per year of the child’s age
(ie 2 year old checked every 2 weeks)
o B) Penalization Therapy
 Blur the image of the sound eye, forcing fixation to the amblyopic eyes
 Adhesive tape on glasses lens, blurring optical lens, atropine
eyes
 Problem with atropine: can be too strong and result in reverse
amblyopia and loss of vision of the sound eye (have constant checkups
to avoid)
 Stop treatment when amblyopic eye’s vision improves to within 1 or 2 Snellen lines
Eye to eye: Amblyopia
DeRespinis: I think we should discuss the different options of occlusion therapy. I think there are four
of them. The first one - occlusion therapy with stick-on patches - obviously is the gold standard, as Dr.
Olitsky mentioned. The second option is atropine. The third option is a slide-on patch, which I think
can work effectively. It's a slide-on felt patch that several companies now make that basically
occludes out above, below, to the temporal side, and to the nasal side very well, but they have to
slide on the glasses. The fourth option - an occlusion contact lens - is fairly controversial. Most
physicians wouldn't use it unless nothing else seemed to be working.
ABCD (Alaska Blind Child Discovery)
http://www.abcd-vision.org/issues/aap-guidelines.html
 ABCD has screened over 16,000 children from 1996 to 2005
Digital cameras for photoscreening must have the flash located near the lens and the ability to
override the "red reflex reduction" feature. The camera must be able to focus on the subject in a dim
illumination, and ideally can zoom so the face can have sufficient image resolution for subsequent
refractive crescent determination.
The American Academy of Pediatrics (AAP) combined with AAO and AAPOS recommend the
following Age-Appropriate Pediatric Vision Screening Guidelines:
Any Child with Systemic Risk Factors or "Warning Signs of Pediatric Eye Disease" should have A
Confirmatory Eye Examination.
Newborns: The pediatrician should observe the appearance of the eyelids and external eyes, then
carefully view the "Red Reflex" with a direct ophthalmoscope to rule out Congenital Cataract.
Infants: Pediatricians should add to regular observation of the face, eyelids and eyes and directed
observation to whether both eyes, and each eye independently, can equally follow an interesting
object (Cover Test and Fixation). The direct ophthalmoscope can be used to check the Enhanced
Brückner Test.
Toddlers: Photoscreening and/or remote autorefraction can determine if your child is focused and
aligned on an interesting object.
Pre-school: Children aged 4 and older should be able to describe or match a distance acuity test. The
pediatrician MUST ASSURE that each eye is tested independently; this is best done byPATCHING THE
UNTESTED EYE.( Photoscreening and remote autorefraction remain valid vision screening measures
in preschool)
School Age: Pediatricians and School Nurses continue to test children for unilateral acuity and can
add tests of binocularity (stereopsis) and color vision.
Digital cameras manufactured such that the flash is located near the lens produce a bright red reflex
in the pupils that can be used to determine risk factors for amblyopia. When a child's eye is not
focused on the camera, a light crescent appears in the pupil instead of a uniform dark red color
produced by a focused, well-aligned eye. ABCD has purchased several digital cameras with flash-tolens distance short enough to produce good photoscreening images. These cameras have been
calibrated for threshold-levels of amblyogenic unequal farsightedness (hyperopic anisometropia) in a
normal young subject (Andrew Arnold) who wore known powered myopic contact lenses to induce
known amounts of unequal farsightedness and astigmatism (Alaska Med. September/October
2004;46(3):63-72). An iPhone 4 has the potential to work as a photoscreener.
Contemporary Issues

Atropine (pharmacologic penalization) vs. Occlusion
o
o
o
2002 PEDIG 6 month study comparing the two in children ages 3 to less than 7
(n=419), mean age 5.3 years
First wearing glasses for 1 month (“refractive adaptation”), then assigned
randomly to 2 groups
 Needed visual acuity in sound eye to be 20/40 or better and 3+ lines of
interocular difference
Outcome: similar mean improvement (79% occlusion, 74% atropine improved)
 BUT improvement initially faster with occlusion and atropine patients
had reduced acuity in the sound eye at 6 months (24 vs. 3%), which did
not persist with follow-up
  both treatments are effective. Occlusion is more rapid but atropine
is easier and higher acceptance
Amount of treatment
Occlusion (how many hours per day?)
 In 2003, PEDIG compared 2 hours daily to 6 hours daily of occlusion treatment for
moderately amblyopic kids ages 3 to <7 (n=189), average 5.2 years
o Result: same for both groups (improved an average of 2.4 lines)
 Parallel study with kids with severe amblyopia
o 6 hours vs. full-time patching
o Result: essentially the same (86% 6 hour kids, 82% full-timers improved at least
3 lines)
Atropine (daily basis or not?)
 2004 PEDIG, daily vs. weekend for kids 3 to <7 (n=168)
 Same improvement
 conclusion: part-time treatment works just as well as full-time
Problems/challenges/risks?
 (Full-time) patching could have low compliance for 5 year olds…easier when on a 3 year
old
o “It’s usually an issue of the parents understanding how important it is to patch”
(Journal of Pediatric Ophthalmology and Strabismus)
o Luckily, newer patches are more skin-friendly or can use felt patches
 Regression
o Little data available….estimates from 6% to 75%
o 2004 PEDIG study. 24% had recurrence of amblyopia (regardless of
occlusion/atropine)
 However, recurrence much less common if weaned off of daily patching
(6 to 2 hours/day) or tapered off (using Bangerter foils aka blurring
glasses lenses)
Screening for amblyopia in preverbal children with photoscreening photographs. II. Sensitivity and
specificity of the MTI Photoscreener
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Photoscreeners: The analysis of all informative photographs resulted in a sensitivity of 65%
and a specificity of 87%
Mostly relied on detection of strabismus
Encyclopedia Britannica online edition: “amblyopia”
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Amblyopia is a reduction in vision in one or both eyes because the brain receives
inferior visual information in early childhood which leads to functional changes in the
brain
Caused by
o Strabismus (misaligned eyes)
o Uncorrected and usually asymmetric (anisometropia) refractive errors
(far/nearsightedness or astigmatism)
o Other factors that disrupt vision, such as congenital cataracts
Amblyopia must be corrected by early childhood or the visual centers of the brain will
suffer (likely) permanent and irreversible damage, which could lead to more vision
problems in the future (especially if vision is lost in the sound eye)
8/2/13
Prevalence and causes of amblyopia in a rural adult population of Chinese the Handan Eye Study
 2.8% of rural Han Chinese adults 30 to 80 years of age
 Underlying causes: anisometropia (67.3%, unequal refracting power), strabismus (5.4%,
misaligned eyes), mixed strabismus and anisometropia (4.4%), visual deprivation (9.8%),
astigmatism association (9.8%, eye can’t focus), and other (3.4%). Of the amblyopia
cases, 47.6% were hypermetropic
Comparison between the plusoptiX and MTI Photoscreeners
 MTI photoscreener:
o sensitivity of 83.6%, specificity of 90.5%, false- positive rate of 9.4%
 PlusoptiX
o sensitivity of 98.9%, specificity of 96.1%, false- positive rate of 3.7%, falsenegative rate of 1.0%, and positive predictive value of 97.9%.
Is photoscreening the best way to catch 'lazy eye'?
http://phys.org/news205131605.html
 KidSight program (Iowa) screened 147,000 kids 2000 to 2009 with photoscreening
 Medical Technology (MTI) Photoscreener used
o Screens for amblyopic risk factors: anisometropia (unequal visual acuity in both eyes),
high nearsightedness, high farsightedness, astigmatism, strabismus
 Volunteers conducted free screenings, images were assessed by a trained reader
 4% of children needed follow-up for possible amblyopia, 80% then
Amblyopia
http://www.sciencedirect.com.ezproxy.middlebury.edu/science/article/pii/S0140673606685814#bb
ib31
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Autorefractor methods had higher sensitivity than visual-acuity screening using HOTV/LEA
Photoscreeners and stereoacuity screening was worse than visual acuity screening
--STANFORD
Amblyopia characterization, Treatment, and Prophylaxis
Kurt Simons
 Reverse amblyopia can arise from excessive administration of treatment (occlusion or
penalization), but tends to be rare and temporary
o “incidence is low and, except in a few cases, not clinically significant”
o Most likely with severely strabismic/daily atropine highly hyperopic patients under 4
years of age
 Other possible risks:
o Mild allergic reactions to penalization
o Facial-flushing
o Light sensitivity 18%
o Conjunctiva irritation 4% (outer membrane of eye)
o Eye pain/headache 2%
 Skin irritation once 41%
 Moderate/severe skin irritation 6%
PARIS
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Photoscreening (take picture and look at how flash reflects the eyes. “red reflex” =
Bruckner test). does this catch anything else? Seems to only be used to catch amblyopic
o
o
o
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Uses Bruckner reflex:
Advantages: easy, fast, cheap, anyone can do it
Disadvantage: only caught 65% of the cases in one study, another study found
56% sensitivity and 91% specificity
NCAR (noncycloplegic autorefraction) – SureSight autorefractor
o Hand-held, batter-operated infrared autorefractor that uses a red-light stimulus
surrounded by 4 flashing green lights as a fixation target.
o “The instrument contains a Hartmann-Schack aberrometer, which extracts
refractive error of the eye from the pattern of infrared light reflected back from
the fundus. The SureSight autorefractor provides a measurement of refractive
error that requires no interpretation of images by the examiner. The unit takes
five separate measurements of each eye and calculates a reliability statistic,
which indicates their consistency.” (PARIS)
o Fastest (1.7 ± 1.0 minutes)
LEA visual acuity: symbols like E chart

Stereopsis (RDE): checks child’s ability to discern depth of distance of an object. Depth
perception needs both eyes to work together to fuse the two images. Wear special
glasses. If the child sees the raised “E”, s/he passes time consuming?
The VF-14 and psychological impact of amblyopia and strabismus.
http://www.ncbi.nlm.nih.gov/pubmed/17003430
Abstract
PURPOSE:
To assess the impact of amblyopia, strabismus and glasses on subjective visual and psychological
function among amblyopes.
METHODS:
Questionnaires were administered to 120 teenagers with amblyopia (cases), with residual amblyopia
after treatment, or with or without strabismus and 120 control subjects (controls) Cases underwent
ophthalmic examination including cycloplegic refraction. Two questionnaires (visual function 14 [VF14] and a newly designed eight-item questionnaire) were administered to assess the psychological
impact score of general daily life, having a weaker eye, glasses wear, and current noticeable
strabismus. Questionnaires were validated in 60 subjects in each group by a second administration
of the questionnaire. The VF-14 scores, psychological impact scores, and clinical data were
compared.
RESULTS:
The VF-14 and psychological impact scores were highly reproducible. The mean VF-14 score for the
control group was 95.5 and for the cases was 78.9 (P < 0.0001), but the scores did not correlate with
the severity of amblyopia. The psychological impact score in general daily life was sensitive in
discriminating between mild (median score 31) and moderate to severe (median score 56)
amblyopes (P < 0.02). The cases segregated into two clear groups; those who scored high (large
detrimental psychological impact) on psychological impact, with subjectively noticeable manifest
strabismus, and those who scored low (low detrimental psychological impact), without noticeable
strabismus. The subjective experience of patching treatment differentiated the two groups best of
all.
CONCLUSIONS:
Subjective visual and psychological functions are altered compared with normal subjects due to
amblyopia, strabismus, and a previous unpleasant patching experience. The mean VF-14 score was
similar to that previously published for patients with glaucoma. The study underlines that amblyopia
and/or strabismus have an impact on teenagers' subjective visual function and well-being.
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Amblyopes: 9% teased mostly or always, 12% worried about losing eyesight mostly/almost
always, 21% avoided outdoor activities sometimes or more often, 41% depressed sometimes
or often
Among amblyopes, 2 groups – severely amblyopic people (noticeable strabismus) were more
affected (higher psychological impact scores)
o Strabismus interfered with work, play, sports in 84-85% cases in teen and adult years.
o Poor self-image 72% teens, 77% adult
Older people: unpleasant patching experience strongly associated with high psychological
impact score
“Horwood et al.found thatthose wearing glasses or with previous patching were 35% to 37%
more likely to be victims of physical and verbal bullying”
VF-14 scores are different between amblyopic & non-amblyopic teenagers, but psychological
impact differed between mild and severe amblyopia (noticeable strabismus or no
strabismus), worse in cases with unpleasant patching experience
The timing of patching treatment and a child’s wellbeing
 n=4473
 50% reduction in bullying for kids who had had preschool screening
o  better to have patching done early
Does amblyopia affect educational, health, and social outcomes?
Findings from 1958 British birth cohort
J S Rahi, P M Cumberland, C S Peckham
Abstract
Objective
To determine any association of amblyopia with diverse educational, health, and social outcomes in
order to inform current debate about population screening for this condition.
Design, setting, and participants
Comparison of 8432 people with normal vision in each eye with 429 (4.8%) people with amblyopia
(childhood unilateral reduced acuity when tested with correction and unaccounted for by eye
disease) from the 1958 British birth cohort, with respect to subsequent health and social functioning.
Results
No functionally or clinically significant differences existed between people with and without
amblyopia in educational outcomes, behavioural difficulties or social maladjustment, participation in
social activities, unintended injuries (school, workplace, or road traffic accidents as driver), general
or mental health and mortality, paid employment, or occupation based social class trajectories.
Conclusions
It may be difficult to distinguish, at population level, between the lives of people with amblyopia and
those without, in terms of several important outcomes. A pressing need exists for further concerted
research on what it means to have amblyopia and, specifically, how this varies with severity and how
it changes with treatment, so that screening programmes can best serve those who have the most to
gain from early identification.
 Amblyopes vs non-amblyopes: same educational tests, target occupation, highest education
received, behavioral problems/maladjustment at home/school, bullying, soprts, social
activities, general health
 Difference: more traffic accidents for moderately to severely amblyopic people
 On average, not disadvantageous to be amblyopic
 Study weakness: relies on parental history and non-ophthalmologist medical examiners for
information, but probably correctly classified nonetheless
 Amblyopes have a lifetime risk of visual impairment or blindness of 1 to 3%
The effect of amblyopia on educational activities of students aged 9 - 15
M. Khalaj, Mohammadi Zeidi, M. R. Gasemi, Ahmad Keshtkar
 N=110, 9-15 year old amblyopic people with glasses
 Parets had low knowledge of amblyopia – 41% of parents only had a primary school
education, only 22.7% had higher education
 Amblyopia is the most common cause of visual impairment in kids and middle-aged adults
 Clinically defined: 2+ lines of difference in visual acuity between the eyes
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Boali Hospital in Gazvin, Iran, 11 patients 9-15 years with amblyopia (strabismus and/or
refractive error after treatment with glasses)
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General Health-Related Quality of Life in Preschool Children with
Strabismus or Amblyopia
Ge Wen, MS, Roberta McKean-Cowdin, PhD, Rohit Varma, MD, MPH, Kristina TarczyHornoch, MD,
DPhil, Susan A. Cotter, OD, MS, Mark Borchert, MD, and Stanley Azen, PhD
on behalf of the Multi-ethnic Pediatric Eye Disease Study Group
Abstract
Objective—To explore the associations of general health-related quality of life (GHRQOL) with
strabismus or amblyopia in preschool children.
Design — Population-based study.
Participants—Sample of children aged 25 to 72 months in the Multi-ethnic Pediatric Eye Disease
Study (MEPEDS).
Methods—The Pediatric Quality of Life Inventory (PedsQL), a measure of GHRQOL, was
administered to the parents of the children.
Main Outcome Measures—The PedsQL consists of 4 sub-scales (physical, emotional, social, and
school functioning) and 3 composite scores (physical summary, psychosocial summary, and total).
Regression models were used to evaluate the associations of GHRQOL with strabismus (in children
25 to 72 months) or amblyopia (in children 30 to 72 months), respectively.
Results—Of the 4,218 children aged ≧25 months, 121 (2.9%) were diagnosed with strabismus.
Significant differences were found in all 3 composite scores between children with and without
strabismus, before and after controlling for gender, age, race, family income, systemic health
conditions, and prior knowledge of strabismus diagnosis (p<0.05). These differences were present in
both esotropes and exotropes, and in both children with intermittent and constant strabismus.
3,318 children were ≧30 months and 71 (2.1%) had amblyopia. There were no significant differences
in any PedsQL scores between children with and without amblyopia, even after adjusting for gender,
age, race, and family income (p>0.05).
Conclusions—Strabismus was associated with significantly worse GHRQOL in preschool children.
While we did not find any detectable association between amblyopia and GHRQOL, further study
using vision-specific instruments is required to explore the impact of both strabismus and amblyopia
on pediatric quality of life.
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Preschool children in southern California – African-American, Hispanic, Asian and NonHispanic White kids
PedsQL = measures pediatric GHRQOL that is not vision-specific. 23 items ranked on a 0-4
scale
Higher magnitude strabismus (10-30 prism diopters) had the worst GHRQOL scores and
differed significantly from the non-strabismus group
Interesting: Strabismus influences significant role in adults selecting a partner or in kids
selecting a playmate (see: another paper)
Other studies found that strabismus causes embarrassment to older patients, and those who
undergo surgery to correct it have significantly improved psychological and physical
functioning (see: another paper)
Age-related trend: 4-5 year old strabismic kids had more problems with more PedsQL items
compared to 2-3 year olds
Not much impact of amblyopia on GHRQOL
o GHRQOL may not be vision-specific enough
o Amblyopia influence may only become apparent at older ages with more visuallydemanding school and sports activities
o Most of the amblyopia in this population was anisometropic rather than strabismic
 not apparent to casual observers
Evaluation of ‘vision screening’ program for three to six-year-old children in the Republic of Iran
Rajiv Khandekar, Noa Parast, and Ashraf Arabi
Abstract
Background:
Since 1996, vision screening of three to six-year-old children is conducted every year in Iran. We
present outcomes of project review held in August 2006.
Materials and Methods:
Kindergarten teachers examined vision by using Snellen’s illiterate ‘E’ chart. They used torchlight to
detect strabismus. On a repeat test, if either eye had vision <20/30, the child was referred to the
optometrist. A pediatric ophthalmologist examined and managed children with strabismus or
amblyopia. Provincial managers supervised the screening program. The evaluator team assessed
the coverage, yield, quality and feasibility, and cost-effectiveness of vision screening, as well as
magnitude of amblyopia, and its risk factors.
Result:
In 2004, 1.4 million (67%) children were examined in all provinces of Iran. Opticians examined
90,319 (61%) children with defective vision that were referred to them. The prevalence of
uncorrected refractive error, strabismus and amblyopia was 3.82% (95% CI 3.79 – 3.85), 0.39% (95%
CI 3.79 – 3.85) and 1.25% (95% CI 31.24 – 1.26) respectively. Validity test of 7.768 children had a
sensitivity of 74.5% (95% CI 72.7 – 76.3) and specificity of 97.2% (95% CI 96.7 – 97.7). The cost of
amblyopia screening was US $1.5 per child. While the cost of screening and treating one child with
amblyopia was US $245.
Conclusion:
A review of the vision screening of children in Iran showed it with screening and useful exercise and
had a yield of 1:21. The coverage of vision screening was low and the management of children with
amblyopia, low vision and refractive error needed strengthening.
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Provincial managers conducted training sessions before school commenced every year to
teach teachers vision screening methods
Teachers make a list of kids with defective vision, tell the parents, refer them to optometrist
o Quality control: provincial managers trained teachers, conducted review meetings,
monitored their activities
Kids not in kindergarten could still come, program staff announced in villages/towns
Used Snellen and flashlight
o Flashlight aimed between 2 eyes from 1 meter away. If reflection of light not in the
center o cornea of either eye  strabismus
Optometrists = 2nd screening level. Repeat vision test, use cycloplegic refraction to prescribe
spectacles
Pediatric ophthalmologists examined referred kids and provided surgical correction for
congenital cataract, congenital glaucoma, strabismus, corneal opacities
Parents contributed US $0.25  parents more involved since they contribute financially
o Program compensated teachers, opticians, ophthalmologists
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Adjusted prevalence of amblyopia 1.25% (how adjusted?)
Cost of screening 1 child: US $1.50
Can the bruckner test be used as a rapid screening test to detect amblyogenic factors in
developing countries?
Kothari MT, Turakhia JK, Vijayalakshmi P, Karthika A, Nirmalan PK.
Abstract
Purpose: To determine the usefulness of the Brückner test as a screening tool for detection of
amblyogenic factors in developing countries.
Methods: A double blind prospective study of 101 children aged 1 to 16 years attending the
pediatric ophthalmology department of a tertiary eye care center. A trained optometrist masked to
clinical findings of the subject performed the Brückner test in a dark room using a direct
ophthalmoscope and compared differences in brightness of the pupillary reflex of both eyes.
Subsequently, subjects underwent a complete ophthalmic examination by a pediatric
ophthalmologist masked to the results of the Brückner test.
Results: The optometrist identified 39 subjects as Brückner test positive and 62 as Brückner test
negative. On clinical examination, 12 subjects had anisometropia of ≥1D and 20 subjects had
manifest deviation of >4(Δ). The sensitivity of the Brückner test was 87.5% and specificity 84.1%; the
positive (PPV) and negative predictive (NPV) value was 71.8% and 93.6%. The false positive and false
negative rates were 28.2% and 6.5%.
Conclusion: Although imperfect, the Brückner test may be a low cost alternative to either screening
with photo screener or to no screening for amblyogenic factors in developing countries.
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References to look up: 4-9 (school screening), 15 (Bruckner)
Difficulties of screening amblyopia on a population basis
o Low prevalence
o Difficulties in accurately measuring vision in children
o No “best test” to screen for amblyopia
o Lack of adequately qualified pediatric ophthalmology personnel to screen the
population
Photoscreener sensitivity supposed to range from 37% to 93% and specificity from 20% to
90% for different amblyogenic factors
o Problem: costs of camera, film and processing
Sample: 1-16 years at a pediatric eye department of an eye center in south India, n=101,
mean 8 years
Study optometrist (<1 year clinical ophthalmology experience, one week training Bruckner
test) and study ophthalmologist independently assessed the subject
Dark room, 1 meter from subject. Measured pupil diameter prior to dark room (Kestenbaum
ruler)
Illuminate both eyes with ophthalmoscope, compare the difference in brightness between
the eyes. If fundus (eye) glow was dull, got closer to the patient
Study ophthalmologist performed clinical examination: dynamic and cycloplegic refraction,
cover test far and close, etc.
1 minute per test
87.5% sensitivity, 84.1% specificity
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Advantages: easy, can train someone with no prior test, cheap, can screen many people,
reasonable accuracy, particularly useful for diagnosing strabismus
Limitations: potentially subjective that could lead to large inter-observer variations, possible
long-term drift in measurement
Concerns: high false positive rate. ¼ identified as having an amblyogenic factor did not have
a problem  costly for further tests
71.8% positive predictive value, high negative predictive value
To improve Bruckner: improve specificity (need better understanding of ways to reduce
intrasubject/interobserver variation) and using the test in high risk/prevalence populations
Sensitivity = proportion of diseased people who were correctly identified by the test
Specificity = proportion of people without the disease who were correctly identified as not
having it
Positive predictive value = proportion of subjects who tested positive who actually had the
disease
Negative predictive value = proportion of subjects who tested negative that actually did not
have the disease
79.2% agreement between study optometrist and ophthalmologist
The Seoul Metropolitan Preschool Vision Screening Programme: results from South Korea
H T Lim, Y S Yu, S-H Park, H Ahn, S Kim, M Lee, J-Y Jeong, K H Shin, B S Koo
Aim: To report on a new model of preschool vision screening that was performed in metropolitan
Seoul and to investigate the distribution of various ocular disorders in this metropolitan preschool
population.
Methods: Vision screening was conducted on 36 973 kindergarten children aged 3–5 years in a
stepwise manner. The first step was home screening using a set of five picture cards and a
questionnaire. The children who did not pass the first step (VA, 0.5 in at least one eye or any
abnormal responses on the questionnaire) were retested with regular vision charts at the regional
public healthcare centres. After this retest, some children were referred to ophthalmologists. The
referral criteria for visual acuity were,0.5 at 3 years and,0.63 at 4 or 5 years in at least one eye.
Results: Of those screened, 7116 (19.2%) children did not pass the home screening tests and 2058
(28.9%) out of the 7116 were referred. The results of the ophthalmological examination in eye clinics
were only available for 894 children (43.4%) of those who were referred. The rest of the children did
not visit ophthalmologists because they had been checked at an eye clinic, were currently under
treatment, or for personal reasons. Refractive errors were found in 608 (1.6%) children. Astigmatism
was associated in 78.2% of ametropes. Amblyopia was discovered in 149 (0.4%) children and
refractive error was the major aetiology with a predominant rate (82.5%). Manifest strabismus was
detected in 52 children. The positive predictive value of vision screening for any ophthalmological
disorder was 0.77, and 0.49 for significant disorders requiring treatment.
Conclusions: This preschool vision screening model was highly accessible to the children and their
parents, easy to administer, and effective to detect a variety of ocular disorders. However, the
participation rate of the referred children in the examinations by ophthalmologists was quite low.
The performance and efficiency of this screening programme need to be optimised with further
revision.


Regular preschool vision program since 1997 in SK
3 steps: home screening with picture cards and answer sheets, retesting in public healthcard
with Jin’s vision chart, referred to eye clinics

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97.1% of ~37,000 participated in home vision screening, 20.2% failed
Only 66.6% of 2058 referred to eye clinics actually went
Limitations:
o 84% of kids who did not visit an eye clinic when referred had already been checked
at eye clinics?
Common Visual Defects and Peer Victimization in Children
Jeremy Horwood, Andrew Waylen, David Herrick, Cathy Williams, Dieter Wolke
PURPOSE.
To investigate whether wearing glasses, having manifest strabismus, or having a history of wearing
an eye patch predisposes preadolescent children to being victimized more frequently at school and
whether the impact may be different on boys than on girls.
METHODS.
Data were examined on 6536 children from the Avon Longitudinal Study of Parents and Children
(ALSPAC) based in the United Kingdom. At 7.5 years, the children undertook a detailed eye
examination by orthoptists, including a cover test and visual acuity assessment. At 8.5 years, trained
psychologists assessed the children’s bullying involvement as either victim or perpetrator for overt
and relational bullying, in a standard interview.
RESULTS.
Children currently wearing glasses or with a history of wearing eye patches were 35% to 37% more
likely to be victims of physical or verbal bullying, even after adjustment for social class and maternal
education. No interactions were found between sex and visual problems in the prediction of bullying.
CONCLUSIONS.
For those children who require glasses, opticians should be aware of the risks of bullying, and
strategies should be developed and discussed that help reduce their vulnerability.
Effect of age on response to amblyopia treatment in children
Jonathan M. Holmes, B.M., Elizabeth L. Lazar, Michele Melia, William F. Astle, Linda R. Dagi, Sean P.
Donahue, Marcela G. Frazier, Richard W. Hertle, Michael X. Repka, Graham E. Quinn, Katherine K.
Weise
Abstract
Objective
To determine whether age at initiation of amblyopia treatment influences the
response among children 3 to <13 years of age with unilateral amblyopia 20/40 to 20/400.
Methods
A meta-analysis of individual subject data from 4 recently completed randomized
amblyopia treatment trials was performed to evaluate the relationship between age and
improvement in logMAR amblyopic eye visual acuity. Analyses were adjusted for baseline
amblyopic eye visual acuity, spherical equivalent refractive error in the amblyopic eye, type of
amblyopia, prior amblyopia treatment, study treatment, and protocol. Age was categorized (3 to
<5 years, 5 to <7 years, and 7 to <13 years) because there was a non-linear relationship between
age and improvement in amblyopic eye acuity.
Results
Subjects 7 to <13 years were significantly less responsive to treatment compared with
younger age groups (3 to <5 years, 5 to <7 years) for moderate and severe amblyopia (P<0.04 for
all four comparisons). There was no difference in treatment response between subjects age 3 to <5
years and 5 to <7 years for moderate amblyopia (P=0.67), but there was a suggestion of greater
responsiveness of 3- to <5-year olds compared with 5- to <7-year olds for severe amblyopia
(P=0.09).
Conclusions
Amblyopia is more responsive to treatment among children younger than age 7
years. Although the average treatment response is smaller in 7- to <13-year olds, some individuals
show a marked response to treatment.
Eye–Hand Coordination Skills in Children with and without Amblyopia
Catherine M. Suttle, Dean R. Melmoth, Alison L. Finlay, John J. Sloper, and Simon Grant
PURPOSE.
To investigate whether binocular information provides benefits for programming and guidance of
reach-to-grasp movements in normal children and whether these eye– hand coordination skills are
impaired in children with amblyopia and abnormal binocularity.
METHODS.
Reach-to-grasp performance of the preferred hand in binocular versus monocular (dominant or
nondominant eye occluded) conditions to different objects (two sizes, three locations, and two to
three repetitions) was quantified by using a 3D motion-capture system. The participants were 36
children (age, 5–11 years) and 11 adults who were normally sighted and 21 children (age, 4 – 8 years)
who had strabismus and/or anisometropia. Movement kinematics and error rates were compared
for each viewing condition within and between subject groups.
RESULTS.
The youngest control subjects used a mainly programmed (ballistic) strategy and collided with the
objects more often when viewing with only one eye, while older children progressively incorporated
visual feedback to guide their reach and, eventually, their grasp, resulting in binocular advantages
for both movement components resembling those of adult performance. Amblyopic children were
the worst performers under all viewing conditions, even when using the dominant eye. They spent
almost twice as long in the final approach to the objects and made many (1.5–3 times) more errors
in reach direction and grip positioning than their normal counterparts, these impairments being
most marked in those with the poorest binocularity, regardless of the severity or cause of their
amblyopia.
CONCLUSIONS.
The importance of binocular vision for eye–hand coordination normally increases with age and use
of online movement guidance. Restoring binocularity in children with amblyopia may improve their
poor hand action control
Amblyopia: Diagnostic and Therapeutic Options
CAROLYN WU, MD, AND DAVID G. HUNTER, MD, PHD
Comparison of preschool vision screening tests as administered by licensed eye care professionals
in the vision in preschoolers study
http://www.aaojournal.org/article/S0161-6420(04)00162-9/abstract#article-footnote-1
Abstract
Purpose
To compare 11 preschool vision screening tests administered by licensed eye care professionals
(LEPs; optometrists and pediatric ophthalmologists).
Design
Multicenter, cross-sectional study.
Participants
A sample (N = 2588) of 3- to 5-year-old children enrolled in Head Start was selected to overrepresent children with vision problems.
Methods
Certified LEPs administered 11 commonly used or commercially available screening tests. Results
from a standardized comprehensive eye examination were used to classify children with respect to 4
targeted conditions: amblyopia, strabismus, significant refractive error, and unexplained reduced
visual acuity (VA).
Main outcome measures
Sensitivity for detecting children with ≥1 targeted conditions at selected levels of specificity was the
primary outcome measure. Sensitivity also was calculated for detecting conditions grouped into 3
levels of importance.
Results
At 90% specificity, sensitivities of noncycloplegic retinoscopy (NCR) (64%), the Retinomax
Autorefractor (63%), SureSight Vision Screener (63%), and Lea Symbols test (61%) were similar.
Sensitivities of the Power Refractor II (54%) and HOTV VA test (54%) were similar to each other.
Sensitivities of the Random Dot E stereoacuity (42%) and Stereo Smile II (44%) tests were similar to
each other and lower (P<0.0001) than the sensitivities of NCR, the 2 autorefractors, and the Lea
Symbols test. The cover–uncover test had very low sensitivity (16%) but very high specificity (98%).
Sensitivity for conditions considered the most important to detect was 80% to 90% for the 2
autorefractors and NCR. Central interpretations for the MTI and iScreen photoscreeners each
yielded 94% specificity and 37% sensitivity. At 94% specificity, the sensitivities were significantly
better for NCR, the 2 autorefractors, and the Lea Symbols VA test than for the 2 photoscreeners for
detecting ≥1 targeted conditions and for detecting the most important conditions.
Conclusions
Screening tests administered by LEPs vary widely in performance. With 90% specificity, the best tests
detected only two thirds of children having ≥1 targeted conditions, but nearly 90% of children with
the most important conditions. The 2 tests that use static photorefractive technology were less
accurate than 3 tests that assess refractive error in other ways. These results have important
implications for screening preschool-aged children.
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
Screening tests need to have high testability, sensitivity and specificity (accurate massscreening)
Phases: I-LEP (licensed eye care professionals), II-trained nurses and lay-people, III-realistic
screening environment
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Done in VIP van w/4 screening rooms
Look at charts for all tests tested
LEA Symbols: cards with square, circle, house, apple linearly arranged
HOTV: exactly like LEA except with HOTV
Random dot E: sample plate with an E, blank plate with random dots, random dot stereo E,
polarizing glasses. First test child with sample and blank plates, then move on to blank and
stereo E
Daylong training
Target conditions: amblyopia, strabismus, significant refractive error
3 groups: severe and urgent (1), important (2), less urgent but should detect (3)
NCR (noncycloplegic retinoscopy) has the best sensitivity for detecting significant refractive
errors or group 1 conditions
Most accurate tests:
o HOTV, Retinomax
Amblyopia: prevalence, natural history, functional effects and treatment 28
Ann L Webber, Joanne Wood
 Amblyopia = lifetime risk of visual loss of at least 1.2%
Two-Year Follow-up of a 6-Month Randomized Trial of Atropine vs Patching for Treatment of
Moderate Amblyopia in Children 29
Objective To compare patching and atropine sulfate as treatments for moderate amblyopia in
children 18 months after completion of a 6-month randomized trial.
Methods In a randomized, multicenter (47 sites) clinical trial, 419 children younger than 7 years
with amblyopia (20/40 to 20/100 in the affected eye) were assigned to receive either patching or
atropine eye drops for 6 months. Between 6 months and 2 years, treatment was at the discretion of
the investigator.
Main Outcome Measure Visual acuity in the amblyopic eye and sound eye after 2 years.
Results At 2 years, visual acuity in the amblyopic eye improved from baseline a mean of 3.7 lines in
the patching group and 3.6 lines in the atropine group. The difference in visual acuity between
treatment groups was small: 0.01 logMAR (95% confidence interval, −0.02 to 0.04). In both
treatment groups, the mean amblyopic eye acuity was approximately 20/32, 1.8 lines worse than
the mean sound eye acuity, which was approximately 20/20.
Conclusions Atropine or patching for 6 months followed by best clinical care until 2 years produced
similar improvement of moderate amblyopia in children between 3 and 7 years of age at enrollment.
However, on average the amblyopic eye acuity was still approximately 2 lines worse than the sound
eye.
A randomized trial of patching regimens for treatment of severe amblyopia in children 30
The Pediatric Eye Disease Investigator Group
Objective: To compare 2 hours vs 6 hours of daily patching as treatments for moderate amblyopia in
children younger than 7 years.
Methods: In a randomized multicenter (35 sites) clinical trial, 189 children younger than 7 years with
amblyopia in the range of 20/40 to 20/80 were assigned to receive either 2 hours or 6 hours daily of
daily patching combined with at least 1 hour per day of near visual activities during patching.
Main Outcome Measure: Visual acuity in the amblyopic eye after 4 months.
Results: Visual acuity in the amblyopic eye improved a similar amount in both groups. The
improvement in the visual acuity of the amblyopic eye from baseline to 4 months averaged 2.40
lines in each group (P=.98). The 4-month visual acuity was at least 20/32 and/or improved from
baseline by 3 or more lines in 62% of patients in each group (P>.99).
Conclusion: When combined with prescribing 1 hour of near visual activities, 2 hours of daily
patching produces an improvement in visual acuity that is of similar magnitude to the improvement
produced by 6 hours of daily patching in treating moderate amblyopia in children aged 3 to 7 years.
Treatment of severe amblyopia with weekend atropine: Results from two randomized clinical
trials 31
Pediatric Eye Disease Investigator Group
Jaeb Center for Health Research, Tampa, Florida
Abstract
Purpose—To determine the effectiveness of weekend atropine for severe amblyopia from
strabismus, anisometropia, or both combined among children 3 to 12 years of age.
Methods—We enrolled children into two prospective, randomized multicenter clinical trials of
amblyopia therapy. Herein we report the results for severe amblyopia, 20/125 to 20/400. In Trial 1,
60 children 3 to 6 years of age (mean, 4.4 years) were randomized to weekend atropine plus a plano
lens or weekend atropine plus full spectacle correction for the sound eye. In Trial 2, 40 children 7 to
12 years of age (mean, 9.3 years) were randomized to weekend atropine or two hours of daily
patching. The visual acuity outcome was assessed at 18 weeks in Trial 1 and 17 weeks in Trial 2.
Results—In Trial 1, visual acuity improved by an average of 4.5 lines in the atropine plus correction
group (95% CI, 3.2-5.8 lines) and 5.1 lines in the atropine plus plano lens group (95% CI, 3.7-6.4
lines). In Trial 2, visual acuity improved by an average of 1.5 lines in the atropine group (95% CI,
0.5-2.5 lines) and 1.8 lines in the patching group (95% CI, 1.1-2.6 lines).
Conclusions—Weekend atropine can improve visual acuity in children 3 to 12 years of age with
severe amblyopia. Improvement may be greater in younger children.
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Residual amblyopia was present after 4 months of treatment in most cases
Typically more improvement in younger subjects
Weekend atropine does improve severe amblyopia, especially in 3 to 6 year olds
Full-time Atropine, Intermittent Atropine, and Optical Penalization and Binocular Outcome in
Treatment of Strabismic Amblyopia 32
Kurt Simons, PhD1, Corresponding author contact information, Leah Stein, OC(C), COMT1, 2, Emin
Cumhur Sener, MD3, Susan Vitale, MHS1, David L. Guyton, MD1
Objective: The purpose of the study is to evaluate the monocular and binocular outcome of three
types of “penalization” (blurring of the sound eye) treatment of amblyopia: traditional full-time
atropine or optical penalization and a new intermittent atropine regimen involving atropine
instillation 1 to 3 days a week.
Design: The study design was a retrospective study.
Participants: A total of 163 patients with strabismic amblyopia treated by full-time atropine (n = 38),
intermittent atropine (n = 73), or optical (n = 52) penalization participated.
Main Outcome Measures: Logarithm of the minimum angle of resolution (logMAR) visual acuity, and
binocularity index were determined.
Results: All three forms of penalization produced statistically significant mean reduction in
amblyopia (1.7–2.7 logMAR lines) and mean improvement in binocularity by the end-of-treatment or
long-term follow-up visit or both, with minimal mean loss after discontinuation or slight mean
improvement on these measures at long-term mean followup of 1.9 to 4 years across groups. Few
patients achieved high-grade stereoacuity. Compliance was high. Comparable efficacy was found for
all three treatment groups after controlling for age, depth of amblyopia, and binocularity at the
initial visit. Initial-visit amblyopia depth was strongly and significantly associated with amblyopia
depth at both post-treatment visits. Pretreatment and post-treatment binocularity showed a similar
strong relationship. Surprisingly, however, there was no consistent or significant association found
between depth of amblyopia and binocularity in any visit combination. Posttreatment measures of
these two variables also were not associated with initial-visit age or refractive error at any clinically
significant level. Mean treatment duration was 1.1 to 2.9 years and was not found to be associated
with visual outcome. Amblyopia reversal was found in one (full-time atropine) case at a clinically
important level.
Conclusions: The authors confirmed previous reports of penalization's efficacy as a primary
treatment of moderate amblyopia (20/100 or better acuity) and, in some cases, relatively severe
amblyopia (>20/100) and also confirmed its ability to significantly improve mean binocularity.
Amblyopia and binocularity appear to respond to treatment independently and, within the
postinfancy age range of the sample studied, the responses appear to be independent of initial-visit
age. The high acceptability to patients and parents of atropine penalization, and particularly of the
intermittent regimen introduced here, suggests the need for prospective-study-based re-evaluation
of the relative merits of penalization and occlusion as the standard of care for mild-to-moderate
amblyopia.
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Advantages of penalization over occlusion;
o Maintains binocular visual field instead of forcing monocularity because sound eye
still has a low-spatial frequency input
o Part-time occlusion can evoke nystagmus (involuntary eye movement) which
penalization
o Less uncomfortable